Distribution of lethal giant larvae (Lgl) protein in the tegument and negative impact of siRNA-based gene silencing on worm surface structure and egg hatching in Schistosoma japonicum

Abstract

Lethal giant larvae (Lgl) are an evolutionarily conserved tumor suppressor present in fungi and animals. It plays an essential role in establishing apical-basal cell polarity, cell proliferation, differentiation, and tissue organization. Here, we report the presence of Lgl gene in the blood fluke Schistosoma japonicum (SjLgl) (GenBank: KF246684). SjLgl protein was mainly distributed in the unique surface tegument structure by immunofluorescence microscopic staining. Using a simple soaking method, a short interfering RNA (siRNA)-based RNA interference approach knocked down the expression of SjLgl in schistosomula in vitro by up to 89.0%. Moreover, tail vein injection of SjLgl-siRNA into the infected mice reduced SjLgl mRNA levels in vivo by 48.6-85.3%, depending on the duration of treatments. SjLgl-specific siRNA treatment during the infection in mice significantly altered the surface structure of adult worm, featured by the disappearance or significant reduction of sharp spines on the inner all of oral and ventral suckers. The siRNA also reduced the hatching rates in eggs produced by treated mice by up to 85.3%. These observations implied that Lgl plays an important role in the development of tegument in schistosomes, and may be explored as a novel target for developing immuno- and/or small molecule-based therapeutics to control and treat the infections caused by schistosome and other flatworms.

The lethal giant larvae Gene in Tribolium castaneum: Molecular Properties and Roles in Larval and Pupal Development as Revealed by RNA Interference

“…Recent studies indicate that the presynaptic Lgl scaffold facilitates the assembly of active zone fusion sites to regulate synaptic vesicle cycling [8]. In Schistosoma japonicum , Lgl plays an important role in the development of tegument as demonstrated by RNA interference (RNAi) [23]. …”

Discovery and Confirmation of Ligand Binding Specificities of the Schistosoma japonicum Polarity Protein Scribble

“…The Scribble polarity module is composed of Scribble, lethal giant larvae (Lgl) and discs large (Dlg), which are well conserved across species from worms and flies to mammals [41], [58]. Recently, it has been shown that the S. japonicum Lgl protein is localized in the worm tegument and knockdown of this gene can significantly deform the surface structure of adult worm and impair egg hatching [59]. To some extent, these data may reveal the potential function of the Scribble polarity module in S. japonicum .…”

Evaluation of Lethal Giant Larvae as a Schistosomiasis Vaccine Candidate

“…Based on our RNA interference experiments, we think LGL plays important roles in the development of S . japonicum embryos [20]. Additionally, we found that the partial sequence from 1866–2711 bp of Sjlgl is conserved in mammalian lgl genes; thus, its potential as a vaccine candidate was investigated.…”

“…Evolutionarily conserved homologs of lgl have been identified in many species, including human, mouse, and worm [17–19] and, in our earlier study, we found that downregulation of the Sjlgl gene affects not only egg hatching but also parasite morphology and that SjLGL mostly localizes to the tegument of adult S. japonicum , even though SjLGL does not contain a signal peptide or transmembrane domain [20]. In this study, we evaluated SjLGL as a candidate schistosomiasis vaccine.…”